Dive computer with global positioning system receiver

ABSTRACT

Dive computers in accordance with embodiments of the invention are disclosed. One embodiment includes a microprocessor, a pressure transducer connected to the microprocessor, a microphone connected to the microprocessor, a speaker connected to the microprocessor, a telephone transceiver connected to the microprocessor, a GPS receiver connected to the microprocessor and a display. In addition, the microprocessor, pressure transducer and display are configured to display information concerning the dive computer&#39;s depth of submersion, the microprocessor, microphone, speaker and telephone transceiver are configured to enable the dive computer to be used as a telephone handset, and the microprocessor is configured to obtain GPS coordinates from the GPS receiver. In a further embodiment, the microprocessor, the microphone, the speaker, the telephone transceiver, the display, and the GPS receiver are components of a mobile phone handset including an external connector for communicating with external devices, the pressure transducer is packaged separately from the mobile phone handset and the pressure transducer packaging includes a connector configured to mate with the external connector of the mobile phone handset creating a connection between the pressure transducer and the microprocessor, and the mobile phone handset and the pressure transducer are contained within a waterproof housing. In addition, a software application installed on the mobile phone handset configures the microprocessor to record information concerning the dive computer&#39;s depth and time of submersion in a dive log.

RELATED CASES

The present application claims priority to U.S. Provisional ApplicationSer. No. 60/977,749 entitled “Dive Computer with Global PositioningSystem Receiver”. The present application also claims priority as acontinuation-in-part to U.S. patent application Ser. No. 12/170,871entitled “Dive Computer with Global Positioning System Receiver”, whichis a divisional of U.S. patent application Ser. No. 11/264,390 nowabandoned. U.S. patent application Ser. No. 11/264,390 is a continuationof U.S. patent application Ser. No. 10/615,635, which claims priority toU.S. Provisional Application Ser. No. 60/394,982, and issued as U.S.Pat. No. 6,972,715. The disclosure of U.S. patent application Ser. Nos.12/170,871, 11/264,390, and 10/615,635, and the disclosure of U.S.Provisional Application Ser. Nos. 60/977,749 and 60/394,982 areincorporated by reference herein in their entirety.

FIELD OF INVENTION

The present invention relates generally to underwater exploration andmore specifically to apparatus and techniques for determining locationduring a dive.

BACKGROUND OF THE INVENTION

The development of self-contained breathing systems has enabled humansto dive and remain underwater for several hours. The ability to remainunderwater for an extended period of time can enable divers to reachconsiderable depths and cover expansive distances in exploringunderwater terrain.

A problem commonly encountered by divers is an inability to accuratelylocate position underwater. Position is typically expressed in terms ofthree co-ordinates. The position of a diver underwater can be expressedin terms of a latitude, a longitude and a depth co-ordinate. Thelatitude and the longitude co-ordinates represent the latitude and thelongitude of a point on the surface of the water directly above thediver. The depth co-ordinate represents the depth of the diver below thesurface of the water. A dive computer similar to a ProPlus 2manufactured by Oceanic Worldwide of San Leandro, Calif. can be used totrack depth during a dive. However, depth alone is insufficient tolocate the position of a diver during a dive.

SUMMARY OF THE INVENTION

Dive computers incorporating a variety of features are disclosed. Oneembodiment includes a processor, a light connected to the processor,where the light is configured to act as a flashlight, a globalpositioning system receiver connected to the processor, the displayconnected to the processor, a pressure transducer connected to theprocessor, and clock circuitry connected to the processor. In addition,the processor is configured to determine time using the clock circuitry,the processor is configured to determine depth of submersion using thepressure transducer, the processor is configured to generate positioninformation using the global positioning system receiver, the processoris configured to provide depth and time information using the display,and the processor is configured to combine the time, depth, and positioninformation into a dive log.

In a further embodiment, the light includes at least one light emittingdiode and the processor is configured to activate the light in responseto input received via the keypad.

Another embodiment includes a processor, a dive computer, an audiodevice, a communication channel connected to the processor and the audiodevice, and the processor is configured to generate a warning alarmusing the audio device in response to a predetermined set of conditions.

A still further embodiment includes a dive computer, a dive maskincorporating an LED display configured to be visible to a diver whenthe dive mask is worn and the LED display is illuminated, and a wirelesscommunication channel between the processor and the LED display. Inaddition, the dive computer is configured to display visual warnings viathe LED display related to decompression.

Still another embodiment includes a processor, a display connected tothe processor, a pressure transducer connected to the processor, clockcircuitry connected to the processor, a keypad connected to theprocessor, and a removable memory connected to the processor. Inaddition, the processor is configured to determine time using the clockcircuitry, the processor is configured to determine depth of submersionusing the pressure transducer, and the processor is configured toprovide depth and time information using the display.

In a yet further embodiment, the removable memory contains audio and/orvideo content.

In yet another embodiment, the removable memory contains informationconcerning a dive site.

A further embodiment again includes a microprocessor, a pressuretransducer connected to the microprocessor, a microphone connected tothe microprocessor, a speaker connected to the microprocessor, atelephone transceiver connected to the microprocessor, and a display. Inaddition, the microprocessor, pressure transducer and display areconfigured to display information concerning the dive computer's depthof submersion, and the microprocessor, microphone, speaker and telephonetransceiver are configured to enable the dive computer to be used as atelephone handset.

Another embodiment again further includes a keypad connected to themicroprocessor. In addition, the microprocessor, telephone transceiverand keypad are configured to enable the entry of text messages fortransmission via the telephone transceiver.

In a further additional embodiment, the telephone transceiver is a cellphone transceiver.

In another additional embodiment, the telephone transceiver is asatellite phone transceiver.

A still yet further embodiment also includes a GPS receiver connected tothe microprocessor. In addition, the microprocessor is configured toobtain GPS coordinates from the GPS receiver.

In still yet another embodiment, the microprocessor is configured totransmit a message containing the GPS coordinates via the telephonetransceiver.

In a further additional embodiment, the microprocessor, the microphone,the speaker, the telephone transceiver, the display, and the GPSreceiver are components of a mobile phone handset including an externalconnector for communicating with external devices, the pressuretransducer is packaged separately from the mobile phone handset and thepressure transducer packaging includes a connector configured to matewith the external connector of the mobile phone handset creating aconnection between the pressure transducer and the microprocessor, andthe mobile phone handset and the pressure transducer are containedwithin a waterproof housing. In addition, a software applicationinstalled on the mobile phone handset configures the microprocessor torecord information concerning the dive computer's depth and time ofsubmersion in a dive log.

In a still further additional embodiment, the software applicationconfigures the mobile handset to upload the dive log to a remote servervia the telephone transceiver.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an embodiment of a dive computerin accordance with practice of the present invention;

FIG. 2 is a flow chart illustrating a method of recording latitude,longitude, depth and time during a dive in accordance with practice ofthe present invention;

FIG. 3 is a flow chart illustrating a method of locating a point ofinterest using data recorded in accordance with practice of the presentinvention;

FIG. 4 is a schematic illustration of a dive computer including a buoyhaving a G.P.S. receiver antenna that is connected to the dive computervia a spool of communication cable;

FIG. 5 is a side view of a submerged diver equipped with a dive computerin accordance with the present invention including a buoy that isdeployed at the surface;

FIG. 6 is a flow chart illustrating a method of recording latitude,longitude, depth and time during a dive in accordance with an embodimentof the present invention that ensures that an automatic measurement oflatitude, longitude and time is made as a dive is commenced;

FIG. 7 is a flow chart illustrating a method of recording locations thata diver considers important;

FIG. 8 is a flow chart illustrating a method of detecting speechcommands in accordance with practice of the present invention;

FIG. 9 is a schematic illustration of an embodiment of a dive computerin accordance with practice of the present invention that includes animpeller and a compass;

FIG. 10A is a side view of a diver equipped with a dive computerattached to an air tank and a wrist mounted display device in accordancewith practice of the present invention;

FIG. 10B is a side view of diver using a dive computer that includes animpeller and a compass that is hose mounted;

FIG. 10C is a side view of diver using a dive computer that includes animpeller and a compass that is wrist mountable;

FIG. 11 is a flow chart illustrating a method of recording latitude,longitude, depth, time, bearing and water speed during a dive inaccordance with an embodiment of the present invention;

FIG. 11A is a flow chart illustrating a method of estimating the coursetaken by a diver based on G.P.S. measurements and water speed, depth andbearing measurements recorded during the dive;

FIG. 12 is a schematic illustration of an embodiment of a dive computerin accordance with an embodiment of the invention that includes apressure transducer for measuring air pressure in an air tank;

FIG. 13 is a flow chart illustrating a process for estimating the rangeof a diver using information concerning air time remaining and waterspeed;

FIG. 14 is a schematic illustration of a dive computer in accordancewith an embodiment of the invention that includes a light;

FIG. 15 is a schematic illustration of a dive computer and a dive maskwith an audio device in accordance with an embodiment of the invention;

FIG. 16 is a schematic illustration of a dive computer and a dive maskwith an visual device in accordance with an embodiment of the invention;

FIG. 17 is a side view of a submerged diver equipped with a divecomputer configured to communicate with a communication device at thesurface in accordance with an embodiment of the invention;

FIG. 18 is a flow chart illustrating a method of communication between adive computer and a communication device at the surface in accordancewith an embodiment of the invention; and

FIG. 19 is a flow chart illustrating a method of communication for adive computer in accordance with an embodiment of the invention.

FIG. 20 is a schematic illustration of a dive computer including amicrophone, speaker and telephone antenna in accordance with anembodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, dive computers in accordance withembodiments of the invention are illustrated. The dive computers makeand record at least measurements of time, depth, and pressure. Thesemeasurements allow the dive computers to calculate whether a diver isascending or descending at a safe rate and whether the diver needs tomake decompression stops. The dive computers also specify the durationof the decompression stops, if they are needed. The dive computerdisplay makes all of this information available to the diver visually.Calculations involving these measurements by the dive computer canindicate the need for warnings to the diver. Warnings to the diver canbe based on air time remaining, unsafe rate of descent or ascent,decompression, or pressure. Warnings can appear on the display of thedive computer. Warnings can also be indicated to the diver by somevisual display other than the display on the dive computer and/oraurally. In several embodiments, divers waiting underwater fordecompression stops or for other reasons can play video and/or audiocontent stored in connection with the dive computer. In this way, adiver who is waiting for any period of time can watch a movie or listento music while waiting.

The dive computers make and record at least three significant sets ofmeasurements, which enable the estimation of the location of points ofinterest underwater and the path traveled by a diver during a dive. Thefirst set of measurements typically includes measurements of latitude,longitude and time immediately prior to the commencement of a dive. Thesecond set of measurements can be generated by periodically measuringdepth and time during a dive. The third set of measurements can becompiled by measuring latitude, longitude and time immediately uponresurfacing from a dive. Following a dive, an estimation of location ata specified time during the dive using these three sets of measurementscan be made by using a number of techniques in accordance with practiceof the present invention. In several embodiments, the accuracy of theestimation can be increased by including measurements of speed andbearing in the second set of measurements.

Turning now to FIG. 1, a dive computer in accordance with practice ofthe present invention is illustrated. The dive computer 10 includes aprocessor 12 that is connected to memory 14, a G.P.S. receiver 16, clockcircuitry 18 and an input/output interface 20. The input/outputinterface 20 is connected to a number of devices that can be used tocommunicate with a user or other devices. In one embodiment, thesedevices include a pressure transducer 22, a keypad 24, a display 26, acommunications port 28 and a microphone 30. A digital camera 32 is alsoprovided as an input device, however, the digital camera bypasses themicroprocessor and is connected directly to the memory 14.

The processor 12 receives information from the G.P.S. receiver 16, theclock circuitry 18 and the input/output interface 20 and selectivelystores the information in memory 14. In one embodiment, the processor isimplemented using a MSP430F149 manufactured by Texas InstrumentsIncorporated of Dallas, Tex. However, the processor could be implementedusing other microprocessors, discrete logic components and/or severalseparate processing elements that share information.

The memory 14 can be used to store data logged by the dive computer 10,to temporarily store information during the performance of calculationsand to store software used to control the operation of the processor 12.The memory 14 need not be a single integrated circuit and can beconstructed from a number of integrated circuits having distinctproperties. In the illustrated embodiment, the memory 14 includesnon-volatile memory circuits 34 to store software for controlling theprocessor 12, manufacturer settings, user settings and calibration data.In addition, the memory 14 also includes a removable memory device 36that is used to store data logged during a dive such as images, a diveprofile, dive logs, GPS logs and/or audio recordings. One aspect ofusing a removable memory device is that individual dives can be loggedon separate removable memory devices and the removable memory devicesused as a method of storing the logged data remote from the divecomputer. In other embodiments, multimedia such as movies and/or musiccan be loaded into the dive computer for viewing via the removablememory. In many embodiments, the removable memory contains informationconcerning a dive site such as marine life common to the area, points ofinterest and/or maps. In embodiments that use a MSP430F149 processor orequivalent processor device, the non-volatile memory included on theprocessor chip can be used to implement the non-volatile memory circuits34 and the removable memory device can be implemented using aSDMB-128-768 128 MB MultiMedia Card manufactured by SanDisk ofSunnyvale, Calif. In other embodiments, memory devices of various sizes,volatility and portability can be used depending on the softwarerequirements of the system and the data logging requirements of theuser. For example, the removable memory device can be replaced by asimilar sized fixed memory device such as an AT2508N-10SI-1.8manufactured by Atmel Corporation of San Jose, Calif. or an equivalentmemory device.

The G.P.S. receiver 16 utilizes signals broadcast from satellites tomake calculations of latitude and longitude. The G.P.S. receiverprovides the latitude and longitude information to the processor, whichis responsible for the processing and storage of the information. In oneembodiment, the G.P.S. receiver is implemented using a GeoHelix-H GPSantenna manufactured by Sarantel Ltd. of Wellingborough, United Kingdom.In other embodiments, other G.P.S. receiver technologies, such as anEmbedded 3.3V G.P.S. Antenna in conjunction with an M-LocJ MPM moduleboth manufactured by Trimble Navigation Limited of Sunnyvale, Calif.,can be used that are capable of providing information to the processorgenerating latitude and longitude co-ordinates.

The clock circuitry 18 can be used to measure the passage of time.Typically the clock circuitry 18 will incorporate a quartz crystal thatis used to generate a periodic signal that can be observed in order tomeasure the passage of time. The clock circuitry 18 can also besynchronized with an external clock to enable time to be expressed inabsolute terms using a time, a day, a month and a year. In oneembodiment the clock circuitry is part of the MSP430F149 microcontrollerdescribed above. In other embodiments, the absolute time can be obtainedusing the G.P.S. receiver 16.

The input/output interface 20 can be constructed from any variety ofwires, antennas, transmitters, receivers, connectors and buffers. Theconfiguration of the input/output interface 20 is dependent on theinput/output devices that are connected to the dive computer. In theembodiment shown in FIG. 1, the input/output devices include a pressuretransducer, a keypad, a display, a communications port and a microphone.In other embodiments, any other combination of input/output devices canbe connected to the dive computer via the input/output interface. In oneembodiment, the portion of the input/output interface connected to thepressure transducer includes a standard analog to digital converter. Inaddition, the input/output interface uses a display driver such as an56B33A1 manufactured by Samsung of Seoul, South Korea to connect tosegment display 26 and a CS53L32A High Speed Analog to Digital convertermanufactured by Cirrus Logic, Inc. of Austin, Tex. to connect to themicrophone 30.

The pressure transducer 22 can be used to measure the pressure of thewater in which the dive computer is immersed. In one embodiment a17887.A Low Pressure Transducer manufactured by Pelagic Pressure Systemsof San Leandro, Calif. can be used to construct the pressure transducer22. In other embodiments, other circuits capable of generating anelectrical signal indicative of the water pressure in which the divecomputer is immersed can be used.

A keypad 24 is typically provided to enable the user to enterinformation concerning the dive or to direct the processor 12 to providethe user with information. In one embodiment, the keypad 24 includes oneor more buttons that can be used to tag the location of the user as apoint of interest. As will be explained in greater detail below, thetagged location can be subsequently retrieved from the memory 14 of thedive computer 10. In other embodiments, the keypad 24 can include one ormore buttons, toggles, joysticks or equivalent devices with which theuser can provide instructions to the processor 12.

A display 26 is typically provided to present information in a graphicalmanner to the user. Information that can be provided to the userincludes a recent G.P.S. reading, depth and/or time. If the divecomputer 10 performs other functions, information relating to thesefunctions can also be communicated using the display 26.

One skilled in the art will appreciate that the connection of keypads 24and displays 26 to dive computers 10 is well known and any number ofpossible configurations, devices and circuitry could be used toestablish a connection between these devices and the processor 12.

The communications port 28 is provided to enable the transfer ofinformation between the dive computer 10 and other devices. In oneembodiment, the communications port 28 is an Integrated Low ProfileTransceiver Module IrDA standard such as the TFDU4100 manufactured byVishay Semiconductor, Inc. of Malvern, Pa. In other embodiments, otherwired or wireless connections and protocols can be used to communicatewith external devices. The transfer of information via thecommunications port 28 enables the movement of data and new softwarebetween the dive computer 10 and other devices. In one embodiment, diveinformation stored in the dive computer memory 14 can be loaded onto apersonal computer and stored, graphed or manipulated. In addition,information from a previous dive stored on an external device can beloaded into the memory 14 of the dive computer for reference during asubsequent dive or information stored within the dive computer can bemanipulated by external devices.

The microphone 30 is provided to enable the audio annotation of datalogged by the dive computer 10. The annotations can be made before,during or after a dive by making a digital recording of the words spokenby the user and associating them with a particular dive or withparticular tagged locations. In other embodiments, automatic speechrecognition could be used to generate textual annotations. The additionof automatic speech recognition technology would also enable the divecomputer to respond to audible instructions from the user. In oneembodiment, the microphone 30 can be a MAB-06A-B manufactured by StarMicronics Company, Ltd. of Edison, N.J. As described above, theinput/output interface 20 can include an analog-to-digital converter forconnection to the microphone. The analog-to-digital converter can samplethe analog signal generated by the microphone 30 and generate a digitalrepresentation of the analog signal. In one embodiment, theanalog-to-digital converter samples the signal from the microphone 30 ata rate of 8 kHz and uses 28 quantization levels to represent the signal.In other embodiments, other sampling rates and a different number ofquantization levels can be used as is appropriate.

In embodiments where automatic speech recognition is used, the processor12 or a discrete device in the input/output interface 20 can convert thedigital representations of the signals from the microphone 30 to text orcommands using hidden Markov models, neural networks, hybrid neuralnetwork/hidden Markov models or other speech modeling or recognitiontechniques. In one embodiment, speech recognition is performed using aRSC-4× Speech Recognition Microcontroller manufactured by Sensory, Inc.of Santa Clara, Calif.

The digital camera 32 is provided to enable the capture of images duringa dive and to enable the use of these images as part of a dive log ifdesired by the user. The digital camera can be implemented using a lensand an array of charge coupled devices both of which are containedwithin the waterproof dive computer housing. In one embodiment, thedigital camera is implemented using a MB86S02A CMOS sensor manufacturedby Fujitsu Microelectronics America, Inc. of Sunnyvale, Calif. tocapture image information and a MCF5307 Direct Memory Access Controllermanufactured by Motorola, Inc. of Schaumburg, Ill. to transfer the imageinformation directly to the memory 14. In other embodiments, anycircuitry capable of capturing a digital image can be used to obtainimage information and store it in memory either via direct memory accessor using the processor 12 in combination with the input/output interface22.

Other input or output devices in addition to those described above canbe connected to a dive computer in accordance with the presentinvention. In one embodiment speakers are connected to the input/outputinterface to enable the playback of recorded speech or to allow a diverto listen to music during a dive. In other embodiments, othercombinations of devices can be used to meet the information requirementsand data recording requirements of a diver during a dive.

Turning now to FIG. 2, a method 40 of recording information during adive that enables estimation of position in accordance with anembodiment of the invention is illustrated. The method includes taking(42) a first G.P.S. measurement, which is performed prior to descending(44) below the surface. Once below the surface, depth and time areperiodically measured (46). After ascending (48) to the surface, asecond G.P.S. measurement is taken (50).

If data is logged during a dive in accordance with the method 40, thenposition during the dive can be estimated. If the user tags a particularlocation during a dive as being of interest, then the user can use thedata logged in accordance with the method 40 shown in FIG. 2 tosubsequently locate the point of interest.

Turning now to FIG. 3, a method of locating a previously identifiedpoint of interest using data logged in accordance with practice of thepresent invention is illustrated. The method 60 includes calculating(62) the duration of the recorded dive, calculating (64) the time thatwas taken to reach the identified point of interest from the start pointof the dive and determining (66) a straight line ‘L’ between the startpoint of the dive and the end point of the dive. Once these functionshave been performed, a value ‘A’ is then calculated (68), which is equalto the length of the line ‘L’ multiplied by the time taken to reach thepoint of interest and divided by the duration of the dive. The value ‘A’is then used to locate (70) a point ‘P’, which is a distance ‘A’ fromthe start point of the dive along the line ‘L’.

Once the point ‘P’ has been identified, a diver can travel (72) to thelatitude and longitude of point ‘P’ and commence a dive. The diver canthen enter the water and descend (74) to the recorded depth of the pointof interest. At this depth, the point of interest can be located bysearching (76) outwardly while attempting to maintain the recorded depthof the point of interest. The depth of a point of interest isparticularly important in relocating that point. The co-ordinatescalculated as the latitude and longitude of a point of interest usingdata collected by a dive computer in accordance with the practice of thepresent invention are simply estimates that place a diver in thevicinity of the point of interest. The knowledge of the depth at whichthe point of interest is located enables the diver to perform anexpanding search in the plane of that depth. Without this information, adiver could be forced to search in three dimensions instead of two. Theadvantages of knowing a depth co-ordinate are increased when the pointof interest forms part of the topography of the sea floor. A diver canrapidly locate such a point of interest by simply descending to therecorded depth of the point of interest and then searching outwardlyfrom the point of descent until a portion of the sea bed is encounteredat the recorded depth of the point of interest. By following thetopography of the sea bed at the depth of the point of interest, thediver has a high likelihood of rapidly relocating the point of interest.

The method 60 illustrated in FIG. 3 can use data recorded in accordancewith the method 40 shown in FIG. 2. The time recorded at the beginningof the dive and the time recorded at the end of the dive can be used tocalculate (62) the duration of the dive. Likewise, the time at thebeginning of the dive and the time recorded at the point of interest canbe used to calculate (64) the time taken to reach the point of interest.The latitude and longitude co-ordinates at the beginning of the dive andthe latitude and longitude co-ordinates at the end of the dive can beused to generate the line ‘L’ (68) and the times calculated above can beused to locate the estimated latitude and longitude of the point ofinterest as described above.

Other techniques can be used to locate a point of interest using datarecorded in accordance with embodiments of the invention. In oneembodiment, the logged data can be used to return to a point of interestby commencing the second dive at the latitude and longitude of whicheverof the start and end points of the earlier dive was closest to the pointof interest. The diver can then travel towards the other of the startand end points. The point of interest can then be located by travelingin this direction at the recorded depth of the point of interest for atime approximating the time it took to travel to the point of interestduring the previous dive.

If a diver seeks to be able to return to a point of interest with a highdegree of accuracy on subsequent dives, then the diver is advised toascend to the surface at the point of interest. The dive computer 10 canthen make a G.P.S. measurement and the diver can be confident thatreturning to the recorded latitude and longitude and descending to therecorded depth will enable rapid location of the point of interest.

An alternative to ascending to the surface is to use the dive computer10′ illustrated in FIG. 4 that includes a compass 70 and a G.P.S.antenna 72 mounted on a buoy 74, which is connected to the othercomponents of the dive computer 75 via a spool 76 of communication cable78. In other embodiments, a wireless connection is used between thespool and the other components of the dive computer. When a diver wishesto take a measurement of latitude and longitude at a point of interest,the buoy is released. At the surface, the antenna can receive thesatellite signals required to measure latitude and longitude. Thesesignals are then conveyed to the G.P.S. receiver via the communicationscable. In other embodiments, additional components such as the entireG.P.S. receiver can be included in the buoy. In one embodiment the spoolis an AR-05 manufactured by Saekodive of Taiwan.

Displacement of the buoy relative to the position of the diver isillustrated in FIG. 5. The displacement of the buoy 74 relative to aposition “P” directly above the diver can be calculated usingPythagorus' theorem by measuring the length of communication cable 78released from the spool 76 and the depth of the diver. The length ofcommunication cable released can be measured using markings on the cable78 and entered in the dive computer manually or via voice command.Alternatively an external line counter could be used that communicatesto the processor of the dive computer via a wireless or wired link. Thedepth of the diver can be measured using the dive computer in the mannerdescribed above. The direction of the displacement can be determinedusing a compass bearing of the cable relative to the diver.

Embodiments of the dive computer in accordance with practice of thepresent invention can enable automatic recording of latitude andlongitude immediately prior to the dive computer 10 descending below thesurface of the water and immediately upon returning to the surface.Turning now to FIG. 6, a method in accordance with practice of thepresent invention for automatically recording the latitude, longitudeand time prior to commencing a dive and upon surfacing from a dive isillustrated. The method 90 includes making (92) and storing (94)measurements of latitude, longitude and time using a G.P.S. receiver.The process of measuring latitude, longitude and time with the G.P.S.receiver and storing the values continues until the diver descends belowthe surface and the answer to the decision (96) of whether the diver hasdescended below the surface becomes affirmative.

Once the diver is below the surface, measurements (98) of depth and timeare made and the measurements are recorded (100) in the memory of thedive computer. The measurement and recording of depth and time continuesfor as long as the diver remains below the surface and until the answerto the decision (102) of whether the diver has surfaced is affirmative.Once the diver has surfaced, a measurement (104) of latitude, longitudeand time is made and the measurement is recorded.

The method 90 described in FIG. 6 can ensure that the measurement storedat the commencement of the dive is the most recent measurement oflatitude, longitude and time that has been made by the G.P.S. receiver16 and dive computer 10. In addition, the method 90 enables periodicmeasurement of depth and time during the dive and the rapid recording oflatitude, longitude and time when the diver resurfaces. In otherembodiments, the logging of latitude, longitude and time can beinitiated in response to user input.

The method 90 shown in FIG. 6 can be modified to enable the diver toidentify points of interest during the dive. Turning now to FIG. 7, amethod in accordance with the practice of the present invention ofidentifying points of interest during a dive is illustrated. The method110 is performed while the diver is under water. The method 110 cancommence with the measurement (112) of depth and time. Once ameasurement of depth and time has been made, the measurements arerecorded (114). Prior to making another measurement of depth and time, acheck is made (116) for any user input. If user input is detected, thenthe previous or next depth and time measurements are identified (118) asa point of interest.

In addition to identifying points of interest, it is desirable to beable to associate information with a point of interest. One advantageousmethod of providing inputs to a dive computer 10 is through the use of amicrophone, as is described above. Speech commands can be used tocontrol the function of the dive computer and speech can be eitherrecorded or converted to text in order to provide description orannotation to a point of interest. In embodiments where speech can berecorded, the recording of speech can be initiated by the pressing of abutton on the keypad 24 or by a voice command recognizable by the divecomputer. In one embodiment, the microphone is contained within a fullface mask enabling speech to be recorded underwater. In otherembodiments, more than one microphone is included so that a diver mayrecord speech using a first microphone and underwater sounds orenvironmental noise using a second microphone. In embodiments of thedive computer 10 that include a digital camera 32, one or more stillimages or a series of still images forming a video sequence can berecorded and associated with a point of interest.

Turning now to FIG. 8, a method in accordance with practice of thepresent invention is illustrated for responding to voice commands. Themethod 130 includes listening (132) for sound. Once sound is detected, adecision (134) is performed to determine if a “voice spotting” sound hasbeen detected. A “voice spotting” sound is a spoken word such as“computer” that can indicate that a user is preparing to speak a commandto a dive computer 10.

If the “voice spotting” sound is detected, then the method involveslistening for a command. A dive computer 10 in accordance with practiceof the present invention will typically have a library of commands eachrequiring different responses from the processor 12. If a sound isheard, then a decision (138) is performed to determine whether the soundcorresponds to one of the commands recognized by the dive computer 10.If a command is recognized, then a response is made (140) to thecommand. Once the response is complete, the process 130 returns tolistening (132) for sound to await the next command.

The method 130 described above uses a “voice spotting” technique. Inother embodiments, “voice spotting” is not required. The speechrecognition performed in “voice spotting” and detecting commands can beeither discrete or continuous recognition. The speech recognition canalso be either speaker dependent or speaker independent. In embodimentswhere annotation of points of interest can be performed, a speechcommand can cause the processor to begin digitally recording speech andto associate the recording with a particular point of interest. In otherembodiments, other forms of user input can be used to identify a pointof interest and to commence the digital recording of speech.Alternatively, a command can cause the processor to convert a passage ofspeech to text using speech recognition techniques and to associate thetext with a point of interest that can be identified using speechcommands or using an alternative user input technique.

As was observed above, latitude, longitude and time measurements made inaccordance with practice of the present invention can be used toestimate the latitude and longitude of a point of interest. The accuracyof this estimate can be effected by currents and the variation in thespeed at which the diver traveled during the dive. The accuracy of theestimated latitude and longitude of a point of interest can be improvedin accordance with the practice of the present invention by takingmeasurements of water speed and bearing as is discussed below.

A dive computer 10″ in accordance with the practice of the presentinvention including an impeller and a compass is illustrated in FIG. 9.The dive computer 10″ is similar to the dive computer 10 illustrated inFIG. 1, but with the addition that an impeller 150 and a compass 152 areconnected to the processor via the input/output interface. Impellers aredevices that generate signals that can be used to measure the flow rateof a liquid or the water speed of the dive computer. By attaching animpeller equipped dive computer to a diver, the output of the impellercan be used to measure the speed at which the diver is moving throughwater and the compass can be used to provide signals to the processorindicative of the direction in which the diver is moving.

In one embodiment, a 3000 impeller manufactured by Nielsen-Kellerman ofChester, Pa., in conjunction with a receiver coil connected to a counterthat can be used to implement the impeller and a HMC 1055 3-axismagnetic sensor manufactured by Honeywell International of Morristown,N.J., that can be used to implement the compass. In other embodimentsother types of flow measurement devices can be used to measure waterspeed.

A diver equipped with a dive computer in accordance with the presentinvention is illustrated in FIG. 10A. The dive computer 160 isimplemented as two discrete components 162 and 164. The first component164 is worn around the wrist of the diver and includes all of thecomponents of the dive computer 10″ illustrated in FIG. 10A except forthe impeller and the compass. The impeller and the compass are locatedin a second component 162 that is fixed to an air tank worn 166 by thediver. In the illustrated embodiment, the two components communicate viaa wireless communications link. In other embodiments, the two componentscan communicate via a wired communications link.

While embodiments shown in FIG. 9 and FIG. 10A include an impeller and acompass, embodiments of the present invention where the parts of thedive computer are distributed between multiple self-contained componentsneed not include an impeller or a compass. In one embodiment, the G.P.S.receiver can be located within a first self-contained component that isattached to the tank, second stage, or thereabouts, and the remainingparts of the dive computer can be located within a second self-containedwatch-like component attached to the diver's wrist or other appropriatepart of the diver's body. In several embodiments, the dive computerincludes multiple self-contained components that are capable ofexchanging information and the parts of the dive computer aredistributed between the multiple self-contained components.

In one embodiment, the dive computer can be contained in a singleself-contained watch-like unit that is attachable to the diver's wristor another appropriate part of the diver's body. In another embodiment,the display, keypad, and microphone can be located in a firstself-contained watch-like component attached to the diver's wrist orother appropriate part of the diver's body and remaining parts of thedive computer can be located within a second self-contained componentattached to the tank, second stage, or thereabouts. In any of theembodiments which involve the dive computer implemented in separatecomponents, the components can communicate via a wired or wirelesscommunication link. In one embodiment, the wireless communication linkis implemented using radio frequency communication. In one embodiment,the wireless communication link is implemented using piezoelectriccommunication. In another embodiment, the wireless communication link isimplemented using magnetic fields.

Returning to embodiments including an impeller and compass, typically adiver is fully extended while swimming and fixing the impeller in adirection parallel to the long axis 168 of the diver as the diver swimsprovides an accurate measurement of the speed of the diver. In addition,mounting the compass so that the bearing measurement is made along aline parallel to the long axis of the diver also enables an accuratemeasurement of bearing to be made. In order accurately align theimpeller and compass, it is desirable that the impeller and the compassbe fixed to maintain a position relative to the body of the diverthroughout the dive. Therefore, in the embodiment illustrated in FIG.10A the impeller and the compass are fixed to the air tank 166 andaligned to be approximately parallel to the long axis 168 of the body ofthe diver, when the diver is fully extended.

In other embodiments, the impeller and the compass can be fixed to otherlocations on the body or equipment of a diver. In many embodiments, thecompass and impeller are included in a single unit with the othercomponents of the dive computer and the position of the impeller and thecompass can be controlled by the diver. A diver can use such a divecomputer in accordance with the present invention to take instantaneouscurrent readings, to use instantaneous speed calculations to calculaterange based on air time remaining (see discussion below) or for anyother application where an instantaneous measurement of speed can beuseful. An example of a hose mounted dive computer 10″ including animpeller and a compass is illustrated in FIG. 10B and an example ofwrist mountable dive computer 10″ including an impeller and a compass isillustrated in FIG. 10C. In several embodiments, accelerometer are usedeither in combination with an impeller or as a substitute for animpeller in order to make distance and velocity measurements.

A method of recording data in accordance with an embodiment of theinvention is shown in FIG. 11. The method 40′ is similar to the method40 illustrated in FIG. 2, with the difference that the periodicmeasurements of depth and time are supplemented with periodicmeasurements of bearing and water speed.

Assuming there is insignificant current, the measurements obtained usingthe process illustrated in FIG. 11 provides a complete map of the coursetaken by a diver. The starting latitude and longitude locations providethe origin of the course and the path followed by the diver can bedetermined using the water speed, bearing, depth and time information.Factors such as drift current can be accounted for by scaling the courseto ensure that it terminates at the location where the diver surfaced,as measured using the G.P.S. receiver. This scaling can be performed bythe dive computer or by an external device that manipulates dataprovided by the dive computer. Drift currents can also be compensatedfor using measurements made by configurations of accelerometers.

In one embodiment, the process illustrated in FIG. 11A is used to adjustor scale the course obtained using recorded water speed and bearingmeasurements in response to the latitude and longitude measurementsobtained at the origin and termination of a dive. The process 170includes defining (172) a planar co-ordinate system at the origin of thedive using the co-ordinates x, y and z, where z represents the depthdimension. Calculating (174) position co-ordinates relative to theorigin of the path taken during the dive using the water speed, depthand bearing data. Determining position co-ordinates of the terminationpoint of the dive based on the water speed, depth and bearing data.Determining (178) position co-ordinates of the termination point of thedive based on the G.P.S. receiver measurements of latitude andlongitude. Calculating (180) the scaling factors that the x and yco-ordinates of the termination point determined using the water speed,depth and bearing data must be multiplied by in order to obtain the xand y co-ordinates of the termination point determined using the G.P.S.receiver measurements of latitude and longitude. An estimate of the pathtaken during the dive is then obtained (182) by scaling the x and yco-ordinates of the points in the path determined using the recordedwater speed, depth and bearing measurements by the calculated scalingfactors. The estimated path can then be output (184) in terms oflatitude, longitude and depth by mapping the co-ordinates of the pathfrom the planar co-ordinate system that was defined relative to theorigin of the dive to latitude, longitude and depth co-ordinates.

An embodiment of a dive computer in accordance with the presentinvention that incorporates pressure transducers in order to measure airtime remaining is illustrated in FIG. 12. The dive computer 10″ includesa pressure transducer 200 that measures air pressure inside an air tank.In one embodiment, the pressure transducer 200 is implemented using ahigh pressure sensor such as a 18519.A manufactured by Pelagic PressureSystems of San Leandro, Calif. Air pressure measurements can beconverted into air time remaining statistics in accordance with themethods described in U.S. Pat. No. 4,586,136 to Lewis and U.S. Pat. No.6,543,444 to Lewis, both of which are incorporated herein by referencein its entirety.

Knowledge of the water speed of the diver and the change in air timeremaining can be used to generate useful information for a diver such asan estimation of the range that a diver can travel with the airremaining in the tanks of the diver. A process for calculating anestimation of range based on the air available to a diver is illustratedin FIG. 13. The process 220 includes recording speed over apredetermined period of time (222) and then calculating the averagespeed during that period of time (224). Once the average speed has beencalculated, the air time remaining is calculated (226). The air timeremaining calculation can be used in combination with the average speedcalculation to predict the range of the diver at current exertionlevels. In other embodiments, the air time remaining can be adjusted toreserve sufficient air to allow the diver to return to the surface fromthe depth at which the diver is located without significant risk ofdecompression sickness.

Underwater light levels can be low and consequently visibility can bedifficult. Thus, a light can be helpful in illuminating a diver'ssurroundings and/or reading the dive computer. An embodiment of a divecomputer in accordance with the present invention that incorporates alight is illustrated in FIG. 14. The dive computer 10.14 includes alight 230.14, a light sensor 232.14, a global positioning system (GPS)receiver 16.14, a digital camera 32.14, a memory 14.14, an input/outputinterface 20.14, a keypad 24.14, a display 26.14, a communications port28.14, a microphone 30.14, a pressure transducer 22.14, and a processor12.14. The processor is connected to the light, light sensor, GPSreceiver, memory, and input/output interface. The input/output interfaceis connected to the keypad, display, communications port, microphone,and pressure transducer. The memory is connected to the digital camera.

In one embodiment, the light can illuminate the dive computer when thediver presses a button on the keypad and/or automatically when the lightsensor indicates the need for the light. The light sensor can measurethe ambient light underwater. In many embodiments, the light or abacklight illuminates the dive computer display. In several embodiments,the light includes one or more light emitting diodes (LEDs). In otherembodiments, the light is configured so that the dive computer can actas a flashlight.

In many embodiments, the processor uses a signal generated by the lightsensor to determine whether to activate the light. For instance, if itis dark underwater, the output generated by the light sensor is below apredetermined threshold, therefore, the processor turns the backlighton. If the signal indicates that there is a sufficient level of ambientlight, then the processor can respond by keeping the backlight off andpreserving the dive computer battery.

During a dive, a diver's attention is often drawn away from the displayof his/her dive computer. Therefore, a period of time typically elapsesbetween the display of a warning by a dive computer and the point intime at which the warning is observed by a diver. Examples of warningsthat can be generated by a dive computer include air time remainingfalling below a predetermined threshold and/or a rate of ascension thatis incompatible with safe decompression. An embodiment of a divecomputer and dive mask with an audio device in accordance with anembodiment of the present invention is illustrated in FIG. 15. Theunderwater audio system includes a dive computer 10.15, a dive mask240.15, and a communication channel 244.15. The dive computer comprisesa processor 12.15, an input/output interface 20.15, and a communicationsport 28.15. The dive mask 240.15 includes an audio device 242.15. Thecommunication channel 244.15 is connected to the communications port28.15 of the dive computer 10.15 and the audio device 242.15 within thedive mask 240.15. The input/output interface 20.15 is connected to theprocessor 12.15 and the communications port 28.15.

In operation, the dive computer can play audio content or sound awarning on the audio device via the communications channel. In oneembodiment, the audio device can be connected to the communications portby a wire. In many embodiments, the audio device can be connected to thecommunications port wirelessly. In one embodiment, wirelesscommunication can be achieved using a communication system that complieswith the Bluetooth, or IEEE 802.15.1, standard. In another embodiment,wireless communication can be achieved using one or more piezoelectricdevices. In yet another embodiment, the wireless communication link canbe implemented using magnetic fields.

In many embodiments, the user of the dive computer can specify whichwarnings will be sent to the audio device by programming the divecomputer. In many embodiments, the audio device can be a pair ofspeakers that are placed in close proximity to the users' ears withinthe diving mask, or earphones. In another embodiment, the audio devicecan be a single speaker. In several embodiments, the speakers can belocated in proximity to the user's ears while outside of the divingmask. In many embodiments, the dive computer can alert the diver aboutlow air supply, decompression requirements, or any other type of warningusing the audio device. The processor can receive signals from sensorsindicating tank air pressure, water pressure, time elapsed, temperatureor other sensor measurements. The processor can use the received signalsto determine which warnings to present to the diver. One set of warningscan be presented to the diver by default. Another set of warnings can bepresented after the dive computer is programmed by the diver.

Warning indicators can also be provided to a diver visually. Anembodiment of a dive computer and dive mask with a visual device inaccordance with the present invention is illustrated in FIG. 16. Theunderwater multimedia system includes a dive computer 10.16, a dive mask240.16, and a communications channel 244.16. The dive computer comprisesa processor 12.16, an input/output interface 20.16, and a communicationsport 28.16. The dive mask 240.16 includes a visual device 250.16. Thecommunication channel 244.16 is connected to the communications port28.16 of the dive computer 10.16 and the visual device 250.16 within thedive mask 240.16. The input/output interface 20.16 is connected to theprocessor 12.16 and the communications port 28.16.

In operation, the dive computer can activate visual warnings on thevisual device via the communications channel. In one embodiment, thevisual device can be connected to the communication port by a wire. Inmany embodiments, the visual device can be connected to thecommunication port wirelessly. In one embodiment, wireless communicationcan be achieved using a communication system that complies with theBluetooth, or IEEE 802.15.1, standard. In another embodiment, wirelesscommunication can be achieved using one or more piezoelectric devices.In several embodiments, the user of the dive computer can specify whichwarnings will be sent to the visual device by programming the divecomputer. In many embodiments, the visual device can include LEDs thatare visually noticeable by the diver. In other embodiments, the visualdevice can be any visual indicator capable of catching the attention ofthe diver when activated. In many embodiments, the dive computer canalert the diver about low air supply, decompression requirements, or anyother warning using the visual device.

Divers often remain at certain depths for relatively long periods oftime for reasons related to decompression. As a diver is waiting, thediver may pass the time by listening to music or watching video storedon the dive computer. A dive computer with a display in accordance withan embodiment of the present invention is illustrated in FIG. 1. Thedive computer 10 comprises a processor 12, a memory 14, an input/outputinterface 20 and a display 26, among the other items discussed with FIG.1 above. The processor is connected to the memory and the input/outputdevice. The input/output device is connected to the display.

In operation, the dive computer can play video content by request of thediver. In many embodiments, the memory can be loaded with audio and/orvideo content. The diver can direct the dive computer to play videocontent using the keypad. The dive computer can respond by showing thestored video on the display. The diver can also listen to the audiocontent associated with the video content using earphones (seediscussion above). In many embodiments, the video is stored in a portionof the memory 14 that is implemented using FLASH memory and/or a harddisk drive. In several embodiments, the video is encoded in a compressedformat that includes information enabling synchronization of the videowith an accompanying audio track. In one embodiment, the processor isconfigured with software to decode the audio and/or video. In otherembodiments, the video and/or audio is decoded using a decoder that isimplemented in hardware.

In several embodiments, the dive computer is configured to enable a userto upload or download video or audio content to the memory. In oneembodiment, content can be loaded externally on a removable memorydevice. The removable memory device can then be connected to the divecomputer and the content accessed by a diver. In one embodiment, thememory capacity can be large enough to accommodate more than three hoursof video content. Three hours of capacity can allow for storage of amovie, television show, or collection of music. In other embodiments,the memory capacity can be large enough to suit whatever storagerequirements a diver might have.

In a number of embodiments, the video is stored in a format thatincludes information restricting access to the video and the processor12 is configured to decode the video in accordance with digital rightsgranted with respect to the video. A group of embodiments storeinformation indicative of digital rights in the memory 14. In a numberof embodiments, the digital rights are stored in an encrypted form.

A user can also direct the dive computer to play audio content using thekeypad. In many embodiments, the audio content is digital music. Inseveral embodiments, the audio content is stored in a compressed format.In a number of embodiments, the audio is stored in a format thatincludes information restricting access to the audio, and the processor12 is configured to decode the audio in accordance with digital rightsgranted with respect to the audio. A group of embodiments storeinformation indicative of digital rights in the memory 14. In a numberof embodiments, the digital rights are stored in an encrypted form.

Often long decompression stops are required at multiple depths leaving adiver to wait underwater for hours. As such, submerged divers often havea desire to communicate with people or computers on the surface. FIG. 17is a side view of a submerged diver equipped with a dive computerconfigured to communicate with a communication device at the surface inaccordance with an embodiment of the present invention. Thecommunication system includes a dive computer 10.17, a communicationcable 252, and a communication device 250 located above the surface ofthe water. The communication cable 252 includes a light 254, a weight256, an underwater connector 258 and a second connector (not shown)capable of being connected to a computer or other communication deviceabove the surface. The dive computer 10.17 includes a keyboard (notshown), a communication port (not shown) capable of being connected withthe underwater connector 258, and a microphone (not shown) or othercommunication equipment allowing the diver or dive computer the abilityto communicate with a person or a communication device at the surface.

The communication cable 252 can include multiple conductors. Theseconductors can include serial communication conductors, power andground. The number of and gauge of serial communication conductors canbe selected to support various physical layer protocols such as RS-232,RS-422, RS-485 or other suitable serial communication system protocols.In other embodiments, parallel communication can be used over aplurality of communication conductors. In one embodiment, one or moreserial communication conductors are fiber optic cables. In oneembodiment, the multiple conductors carry parallel data.

In operation, the communication system allows the diver to recharge herdive computer, talk or exchange messages with people at the surface,download information, and/or minimize decompression stop time. Havingpower available on the communication cable 250 allows the diver torecharge her dive computer battery and provides a stable power source inthe event the dive computer battery is exhausted. This can prove usefulin emergency situations where the dive computer battery is dead and thediver needs to know how to execute her decompression stops.

The power can be supplied at a level appropriate to support the light,one or more dive computers and communication from the dive computers tocommunication devices at the surface. The weight 256 ensures maximumdepth of the lower end of the communication cable when it is loweredinto the water. The light 254 provides a beacon for the diver to findthe communication cable in the event that she has not already connectedher dive computer to the communication cable. In one embodiment, thelight 254 can be any number of colors suitable to get the diver'sattention in a dark underwater environment. In another embodiment, thelight 254 can be a flashing light to further attract a diver's attentionto the communication cable. In other embodiments, other types of beaconscan be used such as sonar or magnetic beacons. In one embodiment, thecommunication cable does not include power. In such case, the light 254can be powered by a battery.

The diver can also use the microphone, keyboard or other input deviceattached to her dive computer to communicate with people via thecommunication device 250 at the surface. In the illustrated embodiment,the communication device at the surface is a computer. In this case, thecommunication can be achieved using two-way audio, text messages or someother communication method. Using the keyboard, microphone or otherinput device, the diver can send details about her dive to people at thesurface. In one embodiment, the diver instructs the dive computer tosend data concerning her recent dive (dive log) to the surface. In thiscase, the information may be processed and analyzed at the surfacebefore the diver returns to the surface. In one embodiment, the diverdiscusses events or issues related to the dive with medical or divesupport personnel at the surface. In this case, the diver can engage inthe discussion using the two-way audio communication or by exchangingtext messages. Audio communication over the communication cable can beimplemented either by transmission of the analog audio or transmissionof a digital representation of the audio using methods known to oneskilled in the art.

The computer at the surface can use the dive log information tocalculate the duration and depth of any required decompression stops. Inthis case, the surface computer can be more powerful or have moreinformation than the dive computer carried by the diver allowing it tomake a more precise calculation of the required decompression stops.This calculation by the surface computer can be relayed to the divecomputer below. In this way, the calculation made possible by thecommunication system can save the diver from waiting at decompressionstops for more time than necessary. Correspondingly, the surfacecalculation can ensure that the diver stays at her decompression stopsfor at least the required decompression time.

In one embodiment, the dive computer downloads audio content from, thesurface computer. In this way, the diver can listen to music, news orother audio content while underwater. More specifically, the diver canaccess this content while ascending or making a decompression stop. Inanother embodiment, the dive computer downloads video content orreceives a video stream and/or audio stream from the surface computer.In this way the diver can watch a movie, television or other audiovisualcontent while underwater. More specifically, the diver can access thiscontent while ascending or making a decompression stop.

A flow chart illustrating a method of communication between a divecomputer and a communication device at the surface in accordance with anembodiment of the invention is shown in FIG. 18. The process firststores (260) information indicative of the depth of submersion and thetime elapsed during submersion. Once such information is stored, theprocess sends (262) the information indicative of the depth ofsubmersion and the time elapsed during submersion to a communicationdevice via a cable including an underwater connector. Once theinformation is sent to the communication device, the process receives(264) information indicative of required decompression stops, where theinformation indicative of required decompression stops is calculated bythe communication device based on the information indicative of depth ofsubmersion and time elapsed during submersion.

A flow chart illustrating a method of communication for a dive computerin accordance with an embodiment of the invention is shown in FIG. 19.The process first measures (270) the depth of submersion and measures(272) the time elapsed during submersion. Once the values are measured,the process stores (274) information including the depth of submersionand the time elapsed during submersion. Once the values are stored, theprocess sends (276) a request for media content. Once the request issent, the process receives (278) media content. Once received, theprocess presents (280) the media content to a diver.

Another dive computer in accordance with an embodiment of the inventionis shown in FIG. 20. The dive computer 10.20 is similar to the divecomputer 10 shown in FIG. 1 with the exception that the dive computer10.20 includes a microphone 30, speaker 300 and telephone transceiversystem 302 that enable the dive computer to act as a telephone handset.In the illustrated embodiment, the microphone 30 and speaker 300 areconnected to the processor 12 via an I/O interface 20 and the telephonetransceiver system 302 is directly connected to the processor 12. Inother embodiments, other configurations of microphones, speakers,telephone transceiver systems and processors are contemplated thatenable the dive computer to be used to make telephone calls via apredetermined telephone network. In a number of embodiments, the divecomputer communicates via a cell phone network such as a D-AMPS,CDMA2000 and/or a GSM network. In other embodiments, the dive computeris configured to communicate via a satellite telephone network and/ormake emergency calls via any of a number of different communicationtechnologies including a satellite telephone network. In severalembodiments, the emergency call includes a digital message containingthe device's current GPS coordinates. In many embodiments, the divecomputer acts as an emergency beacon broadcastings its GPS coordinateson an emergency channel. The circuitry of a dive computer in accordancewith an embodiment of the invention can be configured in a mannerappropriate to the network over which the dive computer can communicateand other circuitry incorporated into the dive computer to enableadditional functionality. Examples of such additional circuitry aredescribed above. In many embodiments, the dive computer includes akeypad enabling the transmission of text messages and emailcommunications from the dive computer via the telephone network. In anumber of embodiments, the dive computer includes a display and the divecomputer is configured to display digital information such as web pages,games, email and other digital information received via the telephonenetwork to which the dive computer can connect in addition toinformation typically associated with a dive computer. In severalembodiments, the information received via the telephone network can bestored on the dive computer. Examples of such information can includeaudio files containing music and multimedia files containing audiovisualpresentations.

A dive computer in accordance with embodiments of the invention can beimplemented using a standard mobile phone handset as the basic platform.Smart phones such as the 3G iPhone manufacture by Apple Inc. ofCupertino, Calif. include a microprocessor, an operating system, atelephone transceiver, a GPS receiver, an external connector, and theability to download applications to the mobile phone handset. When apressure transducer is connected to the smart phone, a softwareapplication installed on the smart phone can perform all of the basicfunctions of a dive computer. In addition, the software application cangenerate a dive log tying in information captured using the pressuretransducer with information captured by components of the mobile phonehandset, such as GPS coordinates acquired using the GPS receiver,accelerometer information for performing dead reckoning, images from acamera, and/or audio recordings. The data capabilities of the mobilephone handset also enable the software application to downloadinformation concerning the dive site and upload information capturedduring the dive, such as a dive log, to a remote server. The multimediacapabilities of the mobile handset also enable the dive computerassembly to act as a media player. During sustained decompression stops,the media player capabilities of the mobile phone handset can beutilized to view video or listen to audio while the dive computerapplication is executing in the background to monitor decompressiontime. In many embodiments, the dive computer application is configuredto interrupt the media player with alerts and/or to notify the diver ofthe completion of a decompression stop. In order for the mobile phonehandset to survive in an underwater environment, the mobile phonehandset and the pressure transducer are typically contained within awaterproof housing. Examples of suitable waterproof housings aredescribed in U.S. Pat. No. 6,396,769 to Polani, and U.S. PatentPublication 2007/0086273 to Polani et al., the disclosure of which isincorporated by reference herein in its entirety. In many embodiments, acombination of external sensors and communication devices are connectedto the mobile phone handset including communication devices that enablewireless communication with other sensors. In a number of embodiments,information is collected from a pressure transducer connected to adiver's air tank and the information is used to perform airtimeremaining calculations.

Although the foregoing embodiments are disclosed as typical, it will beunderstood that additional variations, substitutions and modificationscan be made to the system, as disclosed, without departing from thescope of the invention. For example, embodiments of the invention canhave G.P.S. receivers adapted to be submerged in water that are notconnected to the processor. These embodiments log latitude, longitudeand time information using the G.P.S. receiver and separately log depthand time information using a dive computer. The latitude, longitude andtime information from the G.P.S. receiver and the depth and timeinformation from the dive computer can be downloaded to the divecomputer or another computer and the methods described above can be usedto determine position. In addition, dive computers in accordance withthe present invention can perform functions performed by conventionaldive computers such as providing divers with information concerningdecompression limits or the amount of air remaining in a tank, however,it is not a limitation of the invention that the dive computer performthese functions or other functions typically associated withconventional dive computers. Other functions can also be performed bythe dive computer that are not traditionally associated with divecomputers such as functions normally attributed to personal digitalassistants (P.D.A.s) or other more powerful computing devices. Inaddition, dive computers in accordance with the present invention mayconsist of a conventional dive computer and a microphone and/or adigital camera and do not require the inclusion of a G.P.S. receiver.Other embodiments of dive computers in accordance with the presentinvention may also combine several of the features described above suchas a buoy including a G.P.S. antenna, a compass and an impeller. In oneembodiment, the dive computer has a light powered by a solar cell. In asimilar embodiment, the dive computer has batteries that are rechargedusing a solar cell. In exemplary embodiments, the intensity of the divecomputer backlight can be adjusted by the diver. In one embodiment, theaudio warning can be a high pitched chirping sound. In anotherembodiment, the audio warning can be a constant high pitched sound. Inone embodiment, the video warning can be a powerful repeating flash. Inone embodiment, the dive computer can be configured to operate inconjunction with online video and audio content providers. In oneembodiment, the dive computer can also include a receiver configured toreceive emergency broadcasts. In several embodiments, the playback ofaudio and video content or activation of the backlight can be initiatedusing speech recognition and voice commands. Thus the present inventionhas been described by way of illustration and not limitation.

1. A dive computer comprising: a processor; a light connected to theprocessor, where the light is configured to act as a flashlight; aglobal positioning system receiver connected to the processor; thedisplay connected to the processor; a pressure transducer connected tothe processor; and clock circuitry connected to the processor; whereinthe processor is configured to determine time using the clock circuitry;wherein the processor is configured to determine depth of submersionusing the pressure transducer; wherein the processor is configured togenerate position information using the global positioning systemreceiver; wherein the processor is configured to provide depth and timeinformation using the display; and wherein the processor is configuredto combine the time, depth and position information into a dive log. 2.The dive computer of claim 1, wherein the light includes at least onelight emitting diode and the processor is configured to activate thelight in response to input received via the keypad.
 3. An underwateraudio system comprising: a dive computer comprising: a processor; adisplay connected to the processor; a memory connected to the processor;a pressure transducer connected to the processor; wherein the divecomputer is contained within a waterproof casing; an audio device; acommunication channel connected to the processor and the audio device;wherein the processor is configured to generate a warning alarm usingthe audio device in response to a predetermined set of conditions.
 4. Anunderwater multimedia system comprising: a dive computer comprising: aprocessor; a display connected to the processor; and a waterproofcasing; wherein the dive computer is contained within the waterproofcasing; a dive mask incorporating an LED display configured to bevisible to a diver when the dive mask is worn and the LED display isilluminated; and a wireless communication channel between the processorand the LED display; and wherein the dive computer is configured todisplay visual warnings via the LED display related to decompression. 5.A dive computer comprising: a processor; a display connected to theprocessor; a pressure transducer connected to the processor; clockcircuitry connected to the processor; a keypad connected to theprocessor; and a removable memory connected to the processor; whereinthe processor is configured to determine time using the clock circuitry;wherein the processor is configured to determine depth of submersionusing the pressure transducer; and wherein the processor is configuredto provide depth and time information using the display.
 6. The divecomputer of claim 5, wherein the removable memory contains audio and/orvideo content.
 7. The dive computer of claim 5, wherein the removablememory contains information concerning a dive site.
 8. A dive computer,comprising: a microprocessor; a pressure transducer connected to themicroprocessor; a microphone connected to the microprocessor; a speakerconnected to the microprocessor; a telephone transceiver connected tothe microprocessor; and a display; wherein the microprocessor, pressuretransducer and display are configured to display information concerningthe dive computer's depth of submersion; and wherein the microprocessor,microphone, speaker and telephone transceiver are configured to enablethe dive computer to be used as a telephone handset.
 9. The divecomputer of claim 8, further comprising: a keypad connected to themicroprocessor; wherein the microprocessor, telephone transceiver andkeypad are configured to enable the entry of text messages fortransmission via the telephone transceiver.
 10. The dive computer ofclaim 8, wherein the telephone transceiver is a cell phone transceiver.11. The dive computer of claim 8, wherein the telephone transceiver is asatellite phone transceiver.
 12. The dive computer of claim 8, furthercomprising: a GPS receiver connected to the microprocessor; and whereinthe microprocessor is configured to obtain GPS coordinates from the GPSreceiver.
 13. The dive computer of claim 12, wherein the microprocessoris configured to transmit a message containing the GPS coordinates viathe telephone transceiver.
 14. The dive computer of claim 12, wherein:the microprocessor, the microphone, the speaker, the telephonetransceiver, the display, and the GPS receiver are components of amobile phone handset including an external connector for communicatingwith external devices; the pressure transducer is packaged separatelyfrom the mobile phone handset and the pressure transducer packagingincludes a connector configured to mate with the external connector ofthe mobile phone handset creating a connection between the pressuretransducer and the microprocessor; the mobile phone handset and thepressure transducer are contained within a waterproof housing; and asoftware application installed on the mobile phone handset configuresthe microprocessor to record information concerning the dive computer'sdepth and time of submersion in a dive log.
 15. The device of claim 14,wherein the software application configures the mobile handset to uploadthe dive log to a remote server via the telephone transceiver.